It is called whiteout. It happens when the camera fails to shift from the night time settings to the daytime settings or vice versa. Usually happens in the morning when the sun is up and a animal triggers the camera. Camera takes the pic and the ISO is still set at 1200 or 1400. That is the setting they use at night to absorb all the available light. It is also what creates the grainy pictures. When the camera senses daylight it reverts the ISO back to 200 or 400 for the dayime pics. If this is happening alot you have a bad unit and should be sent in for repair or what ever the company will do for you. Hope this helps,